Verifying historical artifacts in disparate source control systems

ABSTRACT

A computer program product for verifying historical artifacts in disparate source control systems. A processor is configured to: obtain historical artifacts from a target repository; obtain historical artifacts from a source repository; and verify the historical artifacts in the target repository match the historical artifacts in the source repository. Verification further causes the processor to: compare commit data in the historical artifacts in the target repository with commit data in the historical artifacts in the source repository; and evaluate whether each commit data event in the historical artifacts in the target repository is equivalent to the corresponding commit data event in the historical artifacts in the source repository. Evaluation causes the processor to: log a commit data event in the historical artifacts in the target repository which is not equivalent to a corresponding commit data event in the historical artifacts in the source repository; and review the logging results.

BACKGROUND

Embodiments of the invention relate to verifying historical artifacts indisparate source control systems.

As source control systems evolve, the popularity of existing systemsfades and new systems rise to fame. Developers creating new projects caneasily begin using the latest and greatest source control system.However, developers on legacy projects that want to leverage new sourcecontrol systems must migrate their code, and, ideally, their code'shistory. Tools exist to migrate code from existing source controlsystems to newer source control systems, but most of these tools do notverify that the history of commits and comments are accurate, leavingthe person in charge of the migration to manually verify potentiallyhundreds or thousands of events are accurate to ensure historicalartifacts are preserved.

SUMMARY

Embodiments of the invention relate to a computer program product forverifying historical artifacts in disparate source control systems. Thecomputer program product comprising a computer readable storage mediumhaving program instructions embodied therewith, the program instructionsexecutable by a processor to cause the processor to obtain historicalartifacts from a target repository; obtain historical artifacts from asource repository; and verify the historical artifacts in the targetrepository match the historical artifacts in the source repository. Inone embodiment of the present invention, verifying the historicalartifacts match comprises comparing commit data in the historicalartifacts in the target repository with commit data in the historicalartifacts in the source repository; and evaluating whether each commitdata event in the historical artifacts in the target repository isequivalent to the a corresponding commit data event in the historicalartifacts in the source repository. In one embodiment, evaluating theequivalence of commit data in the target and source repositoriescomprises logging a commit data event in the historical artifacts in thetarget repository which is not equivalent to a corresponding commit dataevent in the historical artifacts in the source repository and reviewingthe logging results. In one embodiment, the metadata for the sourcerepository and the target repository is in a standardized format. Inanother embodiment, commit data comprises: commit changes, comments,authorship information, metadata and timestamps. In an embodiment of thepresent invention, a tolerance is established by a user for evaluatingthe commit data in the target and source repositories. Further, thetolerance is a maximum number of differences between a commit data eventin the historical artifacts in the target repository and a correspondingcommit data event in the historical artifacts in the source repository.In one embodiment, each commit data event logged has a number ofdifferences greater than the tolerance.

These and other features, aspects and advantages of the presentinvention will become understood with reference to the followingdescription, appended claims and accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a cloud computing environment, according to anembodiment;

FIG. 2 depicts a set of abstraction model layers, according to anembodiment;

FIG. 3 is a network architecture for verifying historical artifacts indisparate source control systems, according to an embodiment of thepresent invention;

FIG. 4 shows a representative hardware environment that may beassociated with the servers and/or clients of FIG. 1, according to anembodiment; and

FIG. 5 illustrates a block diagram for a process for verifyinghistorical artifacts in disparate source control systems, according toone embodiment.

DETAILED DESCRIPTION

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the describedembodiments. The terminology used herein was chosen to best explain theprinciples of the embodiments, the practical application or technicalimprovement over technologies found in the marketplace, or to enableothers of ordinary skill in the art to understand the embodimentsdisclosed herein.

It is understood in advance that although this disclosure includes adetailed description of cloud computing, implementation of the teachingsrecited herein are not limited to a cloud computing environment. Rather,embodiments of the present invention are capable of being implemented inconjunction with any other type of computing environment now known orlater developed. Also, the verification system could be used to verifyvarious points in time of the repositories. For example, it may beadvantageous to verify that the code is identical at important baselinesor for every delivery/commit.

In an embodiment, the system is configured with location and credentialsto the source and target (migrated) repositories. Implementations areprovided for the source and target repository to obtain and standardizeindividual commit and comment metadata for comparison. The system isconfigurable to match identically or to a certain percentage oftolerance. The system verifies that all historical artifacts areidentical in both repositories. A confidence level is established, afterreview of the verification logs, that the historical artifacts arepreserved.

Cloud computing is a model of service delivery for enabling convenient,on-demand network access to a shared pool of configurable computingresources (e.g., networks, network bandwidth, servers, processing,memory, storage, applications, virtual machines (VMs), and services)that can be rapidly provisioned and released with minimal managementeffort or interaction with a provider of the service. This cloud modelmay include at least five characteristics, at least three servicemodels, and at least four deployment models.

Characteristics are as follows:

On-demand self-service: a cloud consumer can unilaterally provisioncomputing capabilities, such as server time and network storage, asneeded and automatically, without requiring human interaction with theservice's provider.

Broad network access: capabilities are available over a network andaccessed through standard mechanisms that promote use by heterogeneous,thin or thick client platforms (e.g., mobile phones, laptops, and PDAs).

Resource pooling: the provider's computing resources are pooled to servemultiple consumers using a multi-tenant model, with different physicaland virtual resources dynamically assigned and reassigned according todemand. There is a sense of location independence in that the consumergenerally has no control or knowledge over the exact location of theprovided resources but may be able to specify location at a higher levelof abstraction (e.g., country, state, or data center).

Rapid elasticity: capabilities can be rapidly and elasticallyprovisioned and, in some cases, automatically, to quickly scale out andrapidly released to quickly scale in. To the consumer, the capabilitiesavailable for provisioning often appear to be unlimited and can bepurchased in any quantity at any time.

Measured service: cloud systems automatically control and optimizeresource use by leveraging a metering capability at some level ofabstraction appropriate to the type of service (e.g., storage,processing, bandwidth, and active consumer accounts). Resource usage canbe monitored, controlled, and reported, thereby providing transparencyfor both the provider and consumer of the utilized service.

Service Models are as follows:

Software as a Service (SaaS): the capability provided to the consumer isthe ability to use the provider's applications running on a cloudinfrastructure. The applications are accessible from various clientdevices through a thin client interface, such as a web browser (e.g.,web-based email). The consumer does not manage or control the underlyingcloud infrastructure including network, servers, operating systems,storage, or even individual application capabilities, with the possibleexception of limited consumer-specific application configurationsettings.

Platform as a Service (PaaS): the capability provided to the consumer isthe ability to deploy onto the cloud infrastructure consumer-created oracquired applications created using programming languages and toolssupported by the provider. The consumer does not manage or control theunderlying cloud infrastructure including networks, servers, operatingsystems, or storage, but has control over the deployed applications andpossibly application-hosting environment configurations.

Infrastructure as a Service (IaaS): the capability provided to theconsumer is the ability to provision processing, storage, networks, andother fundamental computing resources where the consumer is able todeploy and run arbitrary software, which can include operating systemsand applications. The consumer does not manage or control the underlyingcloud infrastructure but has control over operating systems, storage,deployed applications, and possibly limited control of select networkingcomponents (e.g., host firewalls).

Deployment Models are as follows:

Private cloud: the cloud infrastructure is operated solely for anorganization. It may be managed by the organization or a third party andmay exist on-premises or off-premises.

Community cloud: the cloud infrastructure is shared by severalorganizations and supports a specific community that has shared concerns(e.g., mission, security requirements, policy, and complianceconsiderations). It may be managed by the organizations or a third partyand may exist on-premises or off-premises.

Public cloud: the cloud infrastructure is made available to the generalpublic or a large industry group and is owned by an organization sellingcloud services.

Hybrid cloud: the cloud infrastructure is a composition of two or moreclouds (private, community, or public) that remain unique entities butare bound together by standardized or proprietary technology thatenables data and application portability (e.g., cloud bursting for loadbalancing between clouds).

A cloud computing environment is a service oriented with a focus onstatelessness, low coupling, modularity, and semantic interoperability.At the heart of cloud computing is an infrastructure comprising anetwork of interconnected nodes.

Referring now to FIG. 1, an illustrative cloud computing environment 50is depicted. As shown, cloud computing environment 50 comprises one ormore cloud computing nodes 10 with which local computing devices used bycloud consumers, such as, for example, personal digital assistant (PDA)or cellular telephone 54A, desktop computer 54B, laptop computer 54C,and/or automobile computer system 54N may communicate. Nodes 10 maycommunicate with one another. They may be grouped (not shown) physicallyor virtually, in one or more networks, such as private, community,public, or hybrid clouds as described hereinabove, or a combinationthereof. This allows the cloud computing environment 50 to offerinfrastructure, platforms, and/or software as services for which a cloudconsumer does not need to maintain resources on a local computingdevice. It is understood that the types of computing devices 54A-N shownin FIG. 2 are intended to be illustrative only and that computing nodes10 and cloud computing environment 50 can communicate with any type ofcomputerized device over any type of network and/or network addressableconnection (e.g., using a web browser).

Referring now to FIG. 2, a set of functional abstraction layers providedby the cloud computing environment 50 (FIG. 1) is shown. It should beunderstood in advance that the components, layers, and functions shownin FIG. 2 are intended to be illustrative only and embodiments of theinvention are not limited thereto. As depicted, the following layers andcorresponding functions are provided:

Hardware and software layer 60 includes hardware and softwarecomponents. Examples of hardware components include: mainframes 61; RISC(Reduced Instruction Set Computer) architecture based servers 62;servers 63; blade servers 64; storage devices 65; and networks andnetworking components 66. In some embodiments, software componentsinclude network application server software 67 and database software 68.

Virtualization layer 70 provides an abstraction layer from which thefollowing examples of virtual entities may be provided: virtual servers71; virtual storage 72; virtual networks 73, including virtual privatenetworks; virtual applications and operating systems 74; and virtualclients 75.

In one example, a management layer 80 may provide the functionsdescribed below. Resource provisioning 81 provides dynamic procurementof computing resources and other resources that are utilized to performtasks within the cloud computing environment. Metering and pricing 82provide cost tracking as resources are utilized within the cloudcomputing environment and billing or invoicing for consumption of theseresources. In one example, these resources may comprise applicationsoftware licenses. Security provides identity verification for cloudconsumers and tasks as well as protection for data and other resources.User portal 83 provides access to the cloud computing environment forconsumers and system administrators. Service level management 84provides cloud computing resource allocation and management such thatrequired service levels are met. Service Level Agreement (SLA) planningand fulfillment 85 provide pre-arrangement for, and procurement of,cloud computing resources for which a future requirement is anticipatedin accordance with an SLA.

Workloads layer 90 provides examples of functionality for which thecloud computing environment may be utilized. Examples of workloads andfunctions which may be provided from this layer include: mapping andnavigation 91; software development and lifecycle management 92; virtualclassroom education delivery 93; data analytics processing 94;transaction processing 95 and verifying historical artifacts indisparate source control systems 96. As mentioned above, all of theforegoing examples described with respect to FIG. 2 are illustrativeonly, and the invention is not limited to these examples.

It is understood all functions of one or more embodiments as describedherein may be typically performed in the computing environment 50 (FIG.1), the network 300 (FIG. 3), or performed by the system 400 (FIG. 4),which can be tangibly embodied as hardware processors and with modulesof program code. However, this need not be the case. Rather, thefunctionality recited herein could be carried out/implemented and/orenabled by any of the layers 60, 70, 80 and 90 shown in FIG. 2.

It is reiterated that although this disclosure includes a detaileddescription on cloud computing, implementation of the teachings recitedherein are not limited to a cloud computing environment. Rather, theembodiments of the present invention may be implemented with any type ofclustered computing environment now known or later developed.

FIG. 3 illustrates a network architecture 300, in accordance with oneembodiment. As shown in FIG. 3, a plurality of remote networks 302 areprovided, including a first remote network 304 and a second remotenetwork 306. A gateway 301 may be coupled between the remote networks302 and a proximate network 308. In the context of the present networkarchitecture 300, the networks 304, 306 may each take any formincluding, but not limited to, a LAN, a WAN, such as the Internet,public switched telephone network (PSTN), internal telephone network,etc. In one embodiment, the network architecture 300 employs a POSIX®based file system.

In use, the gateway 301 serves as an entrance point from the remotenetworks 302 to the proximate network 308. As such, the gateway 301 mayfunction as a router, which is capable of directing a given packet ofdata that arrives at the gateway 301, and a switch, which furnishes theactual path in and out of the gateway 301 for a given packet.

Further included is at least one data server 314 coupled to theproximate network 308, which is accessible from the remote networks 302via the gateway 301. It should be noted that the data server(s) 314 mayinclude any type of computing device/groupware. Coupled to each dataserver 314 is a plurality of user devices 316. Such user devices 316 mayinclude a desktop computer, laptop computer, handheld computer, printer,and/or any other type of logic-containing device. It should be notedthat a user device 311 may also be directly coupled to any of thenetworks in some embodiments.

A peripheral 320 or series of peripherals 320, e.g., facsimile machines,printers, scanners, hard disk drives, networked and/or local storageunits or systems, etc., may be coupled to one or more of the networks304, 306, 308. It should be noted that databases and/or additionalcomponents may be utilized with, or integrated into, any type of networkelement coupled to the networks 304, 306, 308. In the context of thepresent description, a network element may refer to any component of anetwork.

According to some approaches, methods and systems described herein maybe implemented with and/or on virtual systems and/or systems, whichemulate one or more other systems, such as a UNIX system that emulatesan IBM z/OS environment, a UNIX system that virtually hosts a MICROSOFTWINDOWS environment, a MICROSOFT WINDOWS system that emulates an IBMz/OS environment, etc. This virtualization and/or emulation may beimplemented through the use of VMWARE software in some embodiments.

FIG. 4 shows a representative hardware system 400 environment associatedwith a user device 316 and/or server 314 of FIG. 3, in accordance withone embodiment. In one example, a hardware configuration includes aworkstation having a central processing unit 410, such as amicroprocessor, and a number of other units interconnected via a systembus 412. The workstation shown in FIG. 4 may include a Random AccessMemory (RAM) 414, Read Only Memory (ROM) 416, an I/O adapter 418 forconnecting peripheral devices, such as disk storage units 420 to the bus412, a user interface adapter 422 for connecting a keyboard 424, a mouse426, a speaker 428, a microphone 432, and/or other user interfacedevices, such as a touch screen, a digital camera (not shown), etc., tothe bus 412, communication adapter 434 for connecting the workstation toa communication network 435 (e.g., a data processing network) and adisplay adapter 436 for connecting the bus 412 to a display device 438.

In one example, the workstation may have resident thereon an operatingsystem, such as the MICROSOFT WINDOWS Operating System (OS), a MAC OS, aUNIX OS, etc. In one embodiment, the system 400 employs a POSIX® basedfile system. It will be appreciated that other examples may also beimplemented on platforms and operating systems other than thosementioned. Such other examples may include operating systems writtenusing JAVA, XML, C, and/or C++ language, or other programming languages,along with an object oriented programming methodology. Object orientedprogramming (OOP), which has become increasingly used to develop complexapplications, may also be used.

FIG. 5 illustrates a block diagram for a process 500 for verifyinghistorical artifacts in disparate source control systems, according toone embodiment of the present invention. A computer program productcomprising a computer readable storage medium having programinstructions embodied therewith, the program instructions executable bya processor to cause the processor to begin in block 502 and obtainhistorical artifacts from a target repository.

After completion of block 502, the process 500 continues with block 504wherein program instructions cause the processor to obtain historicalartifacts from a source repository. After block 504, the process 500continues with block 506 where the processor is instructed to verify thehistorical artifacts in the target repository match the historicalartifacts in the source repository.

In one embodiment of the present invention, verification in block 506comprises sub-block 508 where the processor is instructed to comparecommit data in the historical artifacts in the target repository withcommit data in the historical artifacts in the source repository. Aftercompletion of sub-block 508, the process 500 continues with sub-block510 where the processor is instructed to evaluate whether each commitdata event in the historical artifacts in the target repository isequivalent to the corresponding commit data event in the historicalartifacts in the source repository.

In one embodiment, the evaluation block 510 comprises sub-blocks 512 and514. Block 512 is performed when the processor is instructed to log acommit data event in the historical artifacts in the target repositorywhich is not equivalent to a corresponding commit data event in thehistorical artifacts in the source repository. In an alternativeembodiment, in block 512 the processor will interrupt the verificationprocess when the historical artifacts in the target repository is notequivalent to a corresponding commit data event in the historicalartifacts in the source repository. After completion of block 512, theprocess 500 continues with block 514 wherein a review of the loggingresults is performed.

In one embodiment, the metadata for the source repository and the targetrepository is in a standardized format. In another embodiment, commitdata comprises: commit changes, comments, authorship information,metadata and timestamps. In an embodiment of the present invention, atolerance is established by a user for evaluating the commit data in thetarget and source repositories. Further, the tolerance is a maximumnumber of differences between a commit data event in the historicalartifacts in the target repository and a corresponding commit data eventin the historical artifacts in the source repository. In one embodiment,each commit data event logged has a number of differences greater thanthe tolerance.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, or store a programfor use by or in connection with an instruction execution system,apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described below with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

References in the claims to an element in the singular is not intendedto mean “one and only” unless explicitly so stated, but rather “one ormore.” All structural and functional equivalents to the elements of theabove-described exemplary embodiment that are currently known or latercome to be known to those of ordinary skill in the art are intended tobe encompassed by the present claims. No claim element herein is to beconstrued under the provisions of 35 U.S.C. section 112, sixthparagraph, unless the element is expressly recited using the phrase“means for” or “step for.”

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present invention has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A computer program product for verifyinghistorical artifacts in disparate source control systems, the computerprogram product comprising a computer readable storage medium havingprogram instructions embodied therewith, the program instructionsexecutable by a processor to cause the processor to: obtain, by theprocessor, historical artifacts from a target repository; obtain, by theprocessor, historical artifacts from a source repository; verify, by theprocessor, the historical artifacts in the target repository match thehistorical artifacts in the source repository, further causing theprocessor to: compare, by the processor, commit data in the historicalartifacts in the target repository with commit data in the historicalartifacts in the source repository; and evaluate, by the processor,whether each commit data event in the historical artifacts in the targetrepository is equivalent to the a corresponding commit data event in thehistorical artifacts in the source repository, further causing theprocessor to: log, by the processor, a commit data event in thehistorical artifacts in the target repository which is not equivalent toa corresponding commit data event in the historical artifacts in thesource repository; and review, by the processor, the logging results;wherein: the metadata for the source repository and the targetrepository is in a standardized format; commit data comprises: commitchanges, comments, authorship information, metadata and timestamps; atolerance is established by a user for evaluating the commit data in thetarget and source repositories; the tolerance is a maximum number ofdifferences between a commit data event in the historical artifacts inthe target repository and a corresponding commit data event in thehistorical artifacts in the source repository; and each commit dataevent logged has a number of differences greater than the tolerance.